Hi, Ron, Thanks. I understand now. It may be useful to add a reference to JWT in the KIP.
Jun On Tue, May 15, 2018 at 6:51 PM, Ron Dagostino <rndg...@gmail.com> wrote: > Hi Jun. I think you are getting at the fact that OAuth 2 is a flexible > framework that allows different installations to do things differently. It > is true that the principal name in Kafka could come from any claim in the > token. Most of the time it would come from the 'sub' claim, but it could > certainly come from another claim, or it could be only indirectly based on > a claim value (maybe certain text would be trimmed or prefixed/suffixed). > The point, which I think you are getting at, is that because the framework > is flexible we need to accommodate that flexibility. The callback handler > class defined by the listener.name.sasl_ssl.oauthbearer.sasl.server. > callback.handler.class configuration value gives us the required > flexibility. As an example, I have an implementation that leverages a > popular open source JOSE library to parse the compact serialization, > retrieve the public key if it has not yet been retrieved, verify the > digital signature, and map the 'sub' claim to the OAuthBearerToken's > principal name (which becomes the SASL authorization ID, which becomes the > Kafka principal name). I could just as easily have mapped a different > claim to the OAuthBearerToken's principal name, manipulated the 'sub' claim > value in some way, etc. I write the callback handler code, so I complete > flexibility to do whatever my OAuth 2 installation requires me to do. > > Ron > > On Tue, May 15, 2018 at 1:39 PM, Jun Rao <j...@confluent.io> wrote: > > > Hi, Ron, > > > > Thanks for the reply. I understood your answers to #2 and #3. > > > > For #1, will the server map all clients' principal name to the value > > associated with "sub" claim? How do we support mapping different clients > to > > different principal names? > > > > Jun > > > > On Mon, May 14, 2018 at 7:02 PM, Ron Dagostino <rndg...@gmail.com> > wrote: > > > > > Hi Jun. Thanks for the +1 vote. > > > > > > Regarding the first question about token claims, yes, you have it > correct > > > about translating the OAuth token to a principle name via a JAAS module > > > option in the default unsecured case. Specifically, the OAuth SASL > > Server > > > implementation is responsible for setting the authorization ID, and it > > gets > > > the authorization ID from the OAuthBearerToken's principalName() > method. > > > The listener.name.sasl_ssl.oauthbearer.sasl.server. > > callback.handler.class > > > is responsible for handling an instance of OAuthBearerValidatorCallback > > to > > > accept a token compact serialization from the client and return an > > instance > > > of OAuthBearerToken (assuming the compact serialization validates), and > > in > > > the default unsecured case the builtin unsecured validator callback > > handler > > > defines the OAuthBearerToken.principalName() method to return the > 'sub' > > > claim value by default (with the actual claim it uses being > configurable > > > via the unsecuredValidatorPrincipalClaimName JAAS module option). So > > that > > > is how we translate from a token to a principal name in the default > > > unsecured (out-of-the-box) case. > > > > > > For production use cases, the implementation associated with > > > listener.name.sasl_ssl.oauthbearer.sasl.server.callback.handler.class > > can > > > do whatever it wants. As an example, I have written a class that > wraps a > > > com.nimbusds.jwt.SignedJWT instance (see > > > https://connect2id.com/products/nimbus-jose-jwt/) and presents it as > an > > > OAuthBearerToken: > > > > > > public class NimbusSignedJwtOAuthBearerToken implements > > OAuthBearerToken { > > > private final SignedJWT signedJwt; > > > private final String principalName; > > > private final Set<String> scope; > > > private final Long startTimeMs; > > > private final long lifetimeMs; > > > > > > /** > > > * Constructor > > > * > > > * @param signedJwt > > > * the mandatory signed JWT > > > * @param principalClaimName > > > * the mandatory claim name identifying the claim from > > which > > > the > > > * principal name will be extracted. The claim must > exist > > > and must be > > > * a String. > > > * @param optionalScopeClaimName > > > * the optional claim name identifying the claim from > > which > > > any scope > > > * will be extracted. If specified and the claim exists > > then > > > the > > > * value must be either a String or a String List. > > > * @throws ParseException > > > * if the principal claim does not exist or is not a > > > String; the > > > * scope claim is neither a String nor a String List; > the > > > 'exp' > > > * claim does not exist or is not a number; the 'iat' > > claim > > > exists > > > * but is not a number; or the 'nbf' claim exists and > is > > > not a > > > * number. > > > */ > > > public NimbusSignedJwtOAuthBearerToken(SignedJWT signedJwt, String > > > principalClaimName, > > > String optionalScopeClaimName) throws ParseException { > > > // etc... > > > } > > > > > > The callback handler runs the following code if the digital signature > > > validates: > > > > > > callback.token(new NimbusSignedJwtOAuthBearerToken(signedJwt, > "sub", > > > null)); > > > > > > I hope that answers the first question. If not let me know what I > > > missed/misunderstood and I'll be glad to try to address it. > > > > > > Regarding the second question, the classes OAuthBearerTokenCallback and > > > OAuthBearerValidatorCallback implement the Callback interface -- they > are > > > the callbacks that the AuthenticateCallbackHandler implementations need > > to > > > handle. Specifically, unless the unsecured functionality is what is > > > desired, the two configuration values [listener.name.sasl_ssl. > > oauthbearer. > > > ]sasl.login.callback.handler.class and > > > listener.name.sasl_ssl.oauthbearer.sasl.server.callback.handler.class > > > define the callback handlers that need to handle > OAuthBearerTokenCallback > > > and OAuthBearerValidatorCallback, respectively. > > > > > > Regarding the third question, yes, I see your point that the way the > spec > > > is worded could be taken to imply that the error code is a single > > > character: "A single ASCII..." ( > > > https://tools.ietf.org/html/rfc6749#section-5.2). However, it is not > a > > > single character. See the end of that section 5.2 for an example that > > > shows "error":"invalid_request" as the response. > > > > > > Thanks again for the +1 vote, Jun, and please do let me know if I can > > cover > > > anything else. > > > > > > Ron > > > > > > > > > On Mon, May 14, 2018 at 7:10 PM, Jun Rao <j...@confluent.io> wrote: > > > > > > > Hi, Ron, > > > > > > > > Thanks for the KIP. +1 from me. Just a few minor comments below. > > > > > > > > 1. It seems that we can translate an OAuth token to a principle name > > > > through the claim name configured in JASS. However, it's not clear to > > me > > > > how an OAuth token is mapped to a claim. Could you clarify that? > > > > > > > > 2. The wiki has the following code. It seems that > > > OAuthBearerTokenCallback > > > > should implement AuthenticateCallbackHandler? Ditto > > > > for OAuthBearerValidatorCallback. > > > > > > > > public class OAuthBearerTokenCallback implements Callback > > > > > > > > 3. In OAuthBearerTokenCallback, we have the following method. The > OAuth > > > > spec says the error code is a single ASCII. So, should we return a > Char > > > or > > > > a String? > > > > > > > > public String errorCode() > > > > > > > > Jun > > > > > > > > > > > > On Thu, May 3, 2018 at 8:55 PM, Ron Dagostino <rndg...@gmail.com> > > wrote: > > > > > > > > > Hi everyone. I would like to start the vote for KIP-255: > > > > > https://cwiki.apache.org/confluence/pages/viewpage. > > > > action?pageId=75968876 > > > > > > > > > > This KIP proposes to add the following functionality related to > > > > > SASL/OAUTHBEARER: > > > > > > > > > > 1) Allow clients (both brokers when SASL/OAUTHBEARER is the > > > inter-broker > > > > > protocol as well as non-broker clients) to flexibly retrieve an > > access > > > > > token from an OAuth 2 authorization server based on the declaration > > of > > > a > > > > > custom login CallbackHandler implementation and have that access > > token > > > > > transparently and automatically transmitted to a broker for > > > > authentication. > > > > > > > > > > 2) Allow brokers to flexibly validate provided access tokens when a > > > > client > > > > > establishes a connection based on the declaration of a custom SASL > > > Server > > > > > CallbackHandler implementation. > > > > > > > > > > 3) Provide implementations of the above retrieval and validation > > > features > > > > > based on an unsecured JSON Web Token that function out-of-the-box > > with > > > > > minimal configuration required (i.e. implementations of the two > types > > > of > > > > > callback handlers mentioned above will be used by default with no > > need > > > to > > > > > explicitly declare them). > > > > > > > > > > 4) Allow clients (both brokers when SASL/OAUTHBEARER is the > > > inter-broker > > > > > protocol as well as non-broker clients) to transparently retrieve a > > new > > > > > access token in the background before the existing access token > > expires > > > > in > > > > > case the client has to open new connections. > > > > > > > > > > Thanks, > > > > > > > > > > Ron > > > > > > > > > > > > > > >
